3 perldelta - what is new for perl v5.8.0
7 This document describes differences between the 5.6.0 release
10 Many of the bug fixes in 5.8.0 were already seen in the 5.6.1
11 maintenance release since the two releases were kept closely
14 If you are upgrading from Perl 5.005_03, you might also want
15 to read L<perl56delta>.
17 =head1 Highlights In 5.8.0
23 Better Unicode support
27 New Thread Implementation
35 Better Numeric Accuracy
43 More Extensive Regression Testing
47 =head1 Incompatible Changes
49 =head2 64-bit platforms and malloc
51 If your pointers are 64 bits wide, the Perl malloc is no longer being
52 used because it does not work well with 8-byte pointers. Also,
53 usually the system mallocs on such platforms are much better optimized
54 for such large memory models than the Perl malloc. Some memory-hungry
55 Perl applications like the PDL don't work well with Perl's malloc.
56 Finally, other applications than Perl (like modperl) tend to prefer
57 the system malloc. Such platforms include Alpha and 64-bit HPPA,
60 =head2 AIX Dynaloading
62 The AIX dynaloading now uses in AIX releases 4.3 and newer the native
63 dlopen interface of AIX instead of the old emulated interface. This
64 change will probably break backward compatibility with compiled
65 modules. The change was made to make Perl more compliant with other
66 applications like modperl which are using the AIX native interface.
68 =head2 Attributes for C<my> variables now handled at run-time.
70 The C<my EXPR : ATTRS> syntax now applies variable attributes at
71 run-time. (Subroutine and C<our> variables still get attributes applied
72 at compile-time.) See L<attributes> for additional details. In particular,
73 however, this allows variable attributes to be useful for C<tie> interfaces,
74 which was a deficiency of earlier releases. Note that the new semantics
75 doesn't work with the Attribute::Handlers module (as of version 0.76).
77 =head2 Socket Extension Dynamic in VMS
79 The Socket extension is now dynamically loaded instead of being
80 statically built in. This may or may not be a problem with ancient
81 TCP/IP stacks of VMS: we do not know since we weren't able to test
82 Perl in such configurations.
84 =head2 IEEE-format Floating Point Default on OpenVMS Alpha
86 Perl now uses IEEE format (T_FLOAT) as the default internal floating
87 point format on OpenVMS Alpha, potentially breaking binary compatibility
88 with external libraries or existing data. G_FLOAT is still available as
89 a configuration option. The default on VAX (D_FLOAT) has not changed.
91 =head2 New Unicode Properties
93 Unicode I<scripts> are now supported. Scripts are similar to (and superior
94 to) Unicode I<blocks>. The difference between scripts and blocks is that
95 scripts are the glyphs used by a language or a group of languages, while
96 the blocks are more artificial groupings of (mostly) 256 characters based
97 on the Unicode numbering.
99 In general, scripts are more inclusive, but not universally so. For
100 example, while the script C<Latin> includes all the Latin characters and
101 their various diacritic-adorned versions, it does not include the various
102 punctuation or digits (since they are not solely C<Latin>).
104 A number of other properties are now supported, including C<\p{L&}>,
105 C<\p{Any}> C<\p{Assigned}>, C<\p{Unassigned}>, C<\p{Blank}> and
106 C<\p{SpacePerl}> (along with their C<\P{...}> versions, of course).
107 See L<perlunicode> for details, and more additions.
109 The C<In> or C<Is> prefix to names used with the C<\p{...}> and C<\P{...}>
110 are now almost always optional. The only exception is that a C<In> prefix
111 is required to signify a Unicode block when a block name conflicts with a
112 script name. For example, C<\p{Tibetan}> refers to the script, while
113 C<\p{InTibetan}> refers to the block. When there is no name conflict, you
114 can omit the C<In> from the block name (e.g. C<\p{BraillePatterns}>), but
115 to be safe, it's probably best to always use the C<In>).
117 =head2 REF(...) Instead Of SCALAR(...)
119 A reference to a reference now stringifies as "REF(0x81485ec)" instead
120 of "SCALAR(0x81485ec)" in order to be more consistent with the return
123 =head2 pack/unpack D/F recycled
125 The undocumented pack/unpack template letters D/F have been recycled
126 for better use: now they stand for long double (if supported by the
127 platform) and NV (Perl internal floating point type). (They used
128 to be aliases for d/f, but you never knew that.)
136 The semantics of bless(REF, REF) were unclear and until someone proves
137 it to make some sense, it is forbidden.
141 The obsolete chat2 library that should never have been allowed
142 to escape the laboratory has been decommissioned.
146 The builtin dump() function has probably outlived most of its
147 usefulness. The core-dumping functionality will remain in future
148 available as an explicit call to C<CORE::dump()>, but in future
149 releases the behaviour of an unqualified C<dump()> call may change.
153 The very dusty examples in the eg/ directory have been removed.
154 Suggestions for new shiny examples welcome but the main issue is that
155 the examples need to be documented, tested and (most importantly)
160 The (bogus) escape sequences \8 and \9 now give an optional warning
161 ("Unrecognized escape passed through"). There is no need to \-escape
166 The list of filenames from glob() (or <...>) is now by default sorted
167 alphabetically to be csh-compliant (which is what happened before
168 in most UNIX platforms). (bsd_glob() does still sort platform
169 natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
173 Spurious syntax errors generated in certain situations, when glob()
174 caused File::Glob to be loaded for the first time, have been fixed.
178 Although "you shouldn't do that", it was possible to write code that
179 depends on Perl's hashed key order (Data::Dumper does this). The new
180 algorithm "One-at-a-Time" produces a different hashed key order.
181 More details are in L</"Performance Enhancements">.
185 lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
186 In future releases this may become a fatal error.
190 The C<package;> syntax (C<package> without an argument) has been
191 deprecated. Its semantics were never that clear and its
192 implementation even less so. If you have used that feature to
193 disallow all but fully qualified variables, C<use strict;> instead.
197 The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
198 recognised but now cause fatal errors. The previous behaviour of
199 ignoring them by default and warning if requested was unacceptable
200 since it, in a way, falsely promised that the features could be used.
204 The current user-visible implementation of pseudo-hashes (the weird
205 use of the first array element) is deprecated starting from Perl 5.8.0
206 and will be removed in Perl 5.10.0, and the feature will be
207 implemented differently. Not only is the current interface rather
208 ugly, but the current implementation slows down normal array and hash
209 use quite noticeably. The C<fields> pragma interface will remain
214 The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
218 After years of trying the suidperl is considered to be too complex to
219 ever be considered truly secure. The suidperl functionality is likely
220 to be removed in a future release.
224 The long deprecated uppercase aliases for the string comparison
225 operators (EQ, NE, LT, LE, GE, GT) have now been removed.
229 The tr///C and tr///U features have been removed and will not return;
230 the interface was a mistake. Sorry about that. For similar
231 functionality, see pack('U0', ...) and pack('C0', ...).
235 Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
236 The prototypes are now checked at compile-time for invalid characters.
237 An optional warning is generated ("Illegal character in prototype...")
238 but this may be upgraded to a fatal error in a future release.
242 =head1 Core Enhancements
244 =head2 PerlIO is Now The Default
250 IO is now by default done via PerlIO rather than system's "stdio".
251 PerlIO allows "layers" to be "pushed" onto a file handle to alter the
252 handle's behaviour. Layers can be specified at open time via 3-arg
255 open($fh,'>:crlf :utf8', $path) || ...
257 or on already opened handles via extended C<binmode>:
259 binmode($fh,':encoding(iso-8859-7)');
261 The built-in layers are: unix (low level read/write), stdio (as in
262 previous Perls), perlio (re-implementation of stdio buffering in a
263 portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
264 but available on any platform). A mmap layer may be available if
265 platform supports it (mostly UNIXes).
267 Layers to be applied by default may be specified via the 'open' pragma.
269 See L</"Installation and Configuration Improvements"> for the effects
270 of PerlIO on your architecture name.
274 File handles can be marked as accepting Perl's internal encoding of Unicode
275 (UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
277 open($fh,">:utf8","Uni.txt");
279 Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
280 for you since it's not UTF-8 what you will be getting but instead
281 UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
282 http://www.unicode.org/unicode/reports/tr16/ for more information.
283 In future releases this naming may change.
287 File handles can translate character encodings from/to Perl's internal
288 Unicode form on read/write via the ":encoding()" layer.
292 File handles can be opened to "in memory" files held in Perl scalars via:
294 open($fh,'>', \$variable) || ...
298 Anonymous temporary files are available without need to
299 'use FileHandle' or other module via
301 open($fh,"+>", undef) || ...
303 That is a literal undef, not an undefined value.
307 The list form of C<open> is now implemented for pipes (at least on UNIX):
309 open($fh,"-|", 'cat', '/etc/motd')
311 creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
318 Perl used to be fragile in that signals arriving at inopportune moments
319 could corrupt Perl's internal state. Now Perl postpones handling of
320 signals until it's safe (between opcodes).
322 This change may have surprising side effects because signals no longer
323 interrupt Perl instantly. Perl will now first finish whatever it was
324 doing, like finishing an internal operation (like sort()) or an
325 external operation (like an I/O operation), and only then look at any
326 arrived signals (and before starting the next operation). No more corrupt
327 internal state since the current operation is always finished first,
328 but the signal may take more time to get heard. Note that breaking
329 out from potentially blocking operations should still work, though.
331 =head2 Unicode Overhaul
333 Unicode in general should be now much more usable than in Perl 5.6.0
334 (or even in 5.6.1). Unicode can be used in hash keys, Unicode in
335 regular expressions should work now, Unicode in tr/// should work now,
336 Unicode in I/O should work now.
342 The Unicode Character Database coming with Perl has been upgraded
343 to Unicode 3.1.1. For more information, see http://www.unicode.org/.
347 For developers interested in enhancing Perl's Unicode capabilities:
348 almost all the UCD files are included with the Perl distribution in
349 the F<lib/unicore subdirectory>. The most notable omission, for space
350 considerations, is the Unihan database.
354 The properties \p{Blank} and \p{SpacePerl} have been added. "Blank" is like
355 C isblank(), that is, it contains only "horizontal whitespace" (the space
356 character is, the newline isn't), and the "SpacePerl" is the Unicode
357 equivalent of C<\s> (\p{Space} isn't, since that includes the vertical
358 tabulator character, whereas C<\s> doesn't.)
360 See "New Unicode Properties" earlier in this document for additional
361 information on changes with Unicode properties.
365 =head2 Understanding of Numbers
367 In general a lot of fixing has happened in the area of Perl's
368 understanding of numbers, both integer and floating point. Since in
369 many systems the standard number parsing functions like C<strtoul()>
370 and C<atof()> seem to have bugs, Perl tries to work around their
371 deficiencies. This results hopefully in more accurate numbers.
373 Perl now tries internally to use integer values in numeric conversions
374 and basic arithmetics (+ - * /) if the arguments are integers, and
375 tries also to keep the results stored internally as integers.
376 This change leads to often slightly faster and always less lossy
377 arithmetics. (Previously Perl always preferred floating point numbers
380 =head2 Miscellaneous Changes
386 AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
387 to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
391 C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
392 in multiple arguments.)
396 The builtin dump() now gives an optional warning
397 C<dump() better written as CORE::dump()>,
398 meaning that by default C<dump(...)> is resolved as the builtin
399 dump() which dumps core and aborts, not as (possibly) user-defined
400 C<sub dump>. To call the latter, qualify the call as C<&dump(...)>.
401 (The whole dump() feature is to considered deprecated, and possibly
402 removed/changed in future releases.)
406 chomp() and chop() are now overridable. Note, however, that their
407 prototype (as given by C<prototype("CORE::chomp")> is undefined,
408 because it cannot be expressed and therefore one cannot really write
409 replacements to override these builtins.
413 END blocks are now run even if you exit/die in a BEGIN block.
414 Internally, the execution of END blocks is now controlled by
415 PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
416 behaviour for Perl embedders. This will default in 5.10. See
421 Formats now support zero-padded decimal fields.
425 Lvalue subroutines can now return C<undef> in list context.
426 However, the lvalue subroutine feature still remains experimental.
430 A lost warning "Can't declare ... dereference in my" has been
431 restored (Perl had it earlier but it became lost in later releases.)
435 A new special regular expression variable has been introduced:
436 C<$^N>, which contains the most-recently closed group (submatch).
440 C<no Module;> now works even if there is no "sub unimport" in the Module.
444 The numerical comparison operators return C<undef> if either operand
445 is a NaN. Previously the behaviour was unspecified.
449 The following builtin functions are now overridable: each(), keys(),
450 pop(), push(), shift(), splice(), unshift().
454 C<pack() / unpack()> now can group template letters with C<()> and then
455 apply repetition/count modifiers on the groups.
459 C<pack() / unpack()> can now process the Perl internal numeric types:
460 IVs, UVs, NVs-- and also long doubles, if supported by the platform.
461 The template letters are C<j>, C<J>, C<F>, and C<D>.
465 C<pack('U0a*', ...)> can now be used to force a string to UTF8.
469 my __PACKAGE__ $obj now works.
473 The printf() and sprintf() now support parameter reordering using the
474 C<%\d+\$> and C<*\d+\$> syntaxes. For example
476 print "%2\$s %1\$s\n", "foo", "bar";
478 will print "bar foo\n". This feature helps in writing
479 internationalised software, and in general when the order
480 of the parameters can vary.
484 prototype(\&) is now available.
488 prototype(\[$@%&]) is now available to implicitly create references
489 (useful for example if you want to emulate the tie() interface).
493 A new command-line option, C<-t> is available. It is the
494 little brother of C<-T>: instead of dieing on taint violations,
495 lexical warnings are given. B<This is only meant as a temporary
496 debugging aid while securing the code of old legacy applications.
497 This is not a substitute for -T.>
501 In other taint news, the C<exec LIST> and C<system LIST> have now been
502 considered too risky (think C<exec @ARGV>: it can start any program
503 with any arguments), and now the said forms cause a warning.
504 You should carefully launder the arguments to guarantee their
505 validity. In future releases of Perl the forms will become fatal
506 errors so consider starting laundering now.
510 If tr/// is just counting characters, it doesn't attempt to
515 untie() will now call an UNTIE() hook if it exists. See L<perltie>
520 L<utime> now supports C<utime undef, undef, @files> to change the
521 file timestamps to the current time.
525 The rules for allowing underscores (underbars) in numeric constants
526 have been relaxed and simplified: now you can have an underscore
527 simply B<between digits>.
531 Rather than relying on C's argv[0] (which may not contain a full pathname)
532 where possible $^X is now set by asking the operating system.
533 (eg by reading F</proc/self/exe> on Linux, F</proc/curproc/file> on FreeBSD)
537 A new variable, C<${^TAINT}>, indicates whether taint mode is enabled.
541 You can now override the readline() builtin, and this overrides also
542 the <FILEHANDLE> angle bracket operator.
546 The command-line options -s and -F are now recognized on the shebang
551 =head1 Modules and Pragmata
553 =head2 New Modules and Pragmata
559 C<Attribute::Handlers> allows a class to define attribute handlers.
562 use Attribute::Handlers;
563 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
565 # later, in some package using or inheriting from MyPack...
567 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
569 Both variables and routines can have attribute handlers. Handlers can
570 be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
571 exact compilation phase (BEGIN, CHECK, INIT, or END).
575 B<B::Concise> is a new compiler backend for walking the Perl syntax
576 tree, printing concise info about ops, from Stephen McCamant. The
577 output is highly customisable. See L<B::Concise>.
581 C<Class::ISA> for reporting the search path for a class's ISA tree,
582 by Sean Burke, has been added. See L<Class::ISA>.
586 C<Cwd> has now a split personality: if possible, an XS extension is
587 used, (this will hopefully be faster, more secure, and more robust)
588 but if not possible, the familiar Perl implementation is used.
592 C<Devel::PPPort>, originally from Kenneth Albanowski and now
593 maintained by Paul Marquess, has been added. It is primarily used
594 by C<h2xs> to enhance portability of XS modules between different
599 C<Digest>, frontend module for calculating digests (checksums), from
600 Gisle Aas, has been added. See L<Digest>.
604 C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
605 RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
607 use Digest::MD5 'md5_hex';
609 $digest = md5_hex("Thirsty Camel");
611 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
613 NOTE: the C<MD5> backward compatibility module is deliberately not
614 included since its further use is discouraged.
618 C<Encode>, by Nick Ing-Simmons, provides a mechanism to translate
619 between different character encodings. Support for Unicode,
620 ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
621 compiled in to the module. Several other encodings (like Japanese,
622 Chinese, and MacIntosh encodings) are included and will be loaded at
623 runtime. See L<Encode>.
625 Any encoding supported by Encode module is also available to the
626 ":encoding()" layer if PerlIO is used.
630 C<I18N::Langinfo> can be use to query locale information.
631 See L<I18N::Langinfo>.
635 C<I18N::LangTags> has functions for dealing with RFC3066-style
636 language tags, by Sean Burke. See L<I18N::LangTags>.
640 C<ExtUtils::Constant> is a new tool for extension writers for
641 generating XS code to import C header constants, by Nicholas Clark.
642 See L<ExtUtils::Constant>.
646 C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
647 from Damian Conway. See L<Filter::Simple>.
653 use Filter::Simple sub {
654 while (my ($from, $to) = splice @_, 0, 2) {
663 use MyFilter qr/red/ => 'green';
665 print "red\n"; # this code is filtered, will print "green\n"
666 print "bored\n"; # this code is filtered, will print "bogreen\n"
670 print "red\n"; # this code is not filtered, will print "red\n"
674 C<File::Temp> allows one to create temporary files and directories in
675 an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
679 C<Filter::Util::Call> provides you with the framework to write
680 I<Source Filters> in Perl, from Paul Marquess. For most uses the
681 frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
685 C<if> is a new pragma for conditional inclusion of modules, from
690 L<libnet> is a collection of perl5 modules related to network
691 programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
692 L<Net::Ping>, L<Net::POP3>, L<Net::SMTP>, and L<Net::Time>.
694 Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
698 C<List::Util> is a selection of general-utility list subroutines, like
699 sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
703 C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>, and
704 C<Locale::Language>, from Neil Bowers, have been added. They provide the
705 codes for various locale standards, such as "fr" for France, "usd" for
706 US Dollar, and "jp" for Japanese.
710 $country = code2country('jp'); # $country gets 'Japan'
711 $code = country2code('Norway'); # $code gets 'no'
713 See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
714 and L<Locale::Language>.
718 C<Locale::Maketext> is localization framework from Sean Burke. See
719 L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
720 article about software localization, originally published in The Perl
721 Journal #13, republished here with kind permission.
725 C<Memoize> can make your functions faster by trading space for time,
726 from Mark-Jason Dominus. See L<Memoize>.
730 C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
731 as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
736 $encoded = encode_base64('Aladdin:open sesame');
737 $decoded = decode_base64($encoded);
739 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
745 C<MIME::QuotedPrint> allows you to encode data in quoted-printable
746 encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
747 Extensions)>, from Gisle Aas.
749 use MIME::QuotedPrint;
751 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
752 $decoded = decode_qp($encoded);
754 print $encoded, "\n"; # "Smiley in Unicode: =263A"
756 MIME::QuotedPrint has been enhanced to provide the basic methods
757 necessary to use it with PerlIO::Via as in :
759 use MIME::QuotedPrint;
760 open($fh,">Via(MIME::QuotedPrint)",$path);
762 See L<MIME::QuotedPrint>.
766 C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
771 C<open> is a new pragma for setting the default I/O disciplines
776 C<PerlIO::Scalar> provides the implementation of IO to "in memory"
777 Perl scalars as discussed above, from Nick Ing-Simmons. It also
778 serves as an example of a loadable PerlIO layer. Other future
779 possibilities include PerlIO::Array and PerlIO::Code.
780 See L<PerlIO::Scalar>.
784 C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
785 functionality provided by a class (typically implemented in perl
786 code), from Nick Ing-Simmons.
788 use MIME::QuotedPrint;
789 open($fh,">Via(MIME::QuotedPrint)",$path);
791 This will automatically convert everything output to C<$fh>
792 to Quoted-Printable. See L<PerlIO::Via>.
796 C<Pod::ParseLink>, by Russ Allbery, has been added,
797 to parse LZ<><> links in pods as described in the new
802 C<Pod::Text::Overstrike>, by Joe Smith, has been added.
803 It converts POD data to formatted overstrike text.
804 See L<Pod::Text::Overstrike>.
808 C<Scalar::Util> is a selection of general-utility scalar subroutines,
809 like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
813 C<sort> is a new pragma for controlling the behaviour of sort().
817 C<Storable> gives persistence to Perl data structures by allowing the
818 storage and retrieval of Perl data to and from files in a fast and
819 compact binary format, from Raphael Manfredi. See L<Storable>.
823 C<Switch>, from Damian Conway, has been added. Just by saying
827 you have C<switch> and C<case> available in Perl.
833 case 1 { print "number 1" }
834 case "a" { print "string a" }
835 case [1..10,42] { print "number in list" }
836 case (@array) { print "number in list" }
837 case /\w+/ { print "pattern" }
838 case qr/\w+/ { print "pattern" }
839 case (%hash) { print "entry in hash" }
840 case (\%hash) { print "entry in hash" }
841 case (\&sub) { print "arg to subroutine" }
842 else { print "previous case not true" }
849 C<Test::More> is yet another framework for writing test scripts,
850 more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
854 C<Test::Simple> has basic utilities for writing tests, by Michael
855 Schwern. See L<Test::Simple>.
859 C<Text::Balanced> has been added, for extracting delimited text
860 sequences from strings, from Damian Conway.
862 use Text::Balanced 'extract_delimited';
864 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
866 $a will be "'never say never'", $b will be ', he never said'.
868 In addition to extract_delimited() there are also extract_bracketed(),
869 extract_quotelike(), extract_codeblock(), extract_variable(),
870 extract_tagged(), extract_multiple(), gen_delimited_pat(), and
871 gen_extract_tagged(). With these you can implement rather advanced
872 parsing algorithms. See L<Text::Balanced>.
876 C<threads> is an interface to interpreter threads, by Arthur Bergman.
877 Interpreter threads (ithreads) is the new thread model introduced in
878 Perl 5.6 but only available as an internal interface for extension
879 writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
883 C<threads::shared> allows data sharing for interpreter threads, from
884 Arthur Bergman. In the ithreads model any data sharing between
885 threads must be explicit, as opposed to the old 5.005 thread model
886 where data sharing was implicit. See L<threads::shared>.
890 C<Tie::File>, by Mark-Jason Dominus, associates a Perl array with the
895 C<Tie::Memoize>, by Ilya Zakharevich, provides on-demand loaded hashes.
899 C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
900 references (unlike the standard Tie::RefHash) The module is contained
901 within Tie::RefHash, see L<Tie::RefHash>.
905 C<Time::HiRes> provides high resolution timing (ualarm, usleep,
906 and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
910 C<Unicode::UCD> offers a querying interface to the Unicode Character
911 Database. See L<Unicode::UCD>.
915 C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
916 for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
920 C<Unicode::Normalize> implements the various Unicode normalization
921 forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
925 C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
926 typemaps. Nothing gets installed but for extension writers the code
931 =head2 Updated And Improved Modules and Pragmata
937 The following independently supported modules have been updated to the
938 newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
939 Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
940 (Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
941 Term::ANSIColor, Test, Text-Tabs+Wrap.
945 The attributes::reftype() now works on tied arguments.
949 AutoLoader can now be disabled with C<no AutoLoader;>.
953 B::Deparse has been significantly enhanced. It now can deparse almost
954 all of the standard test suite (so that the tests still succeed).
955 There is a make target "test.deparse" for trying this out.
959 Class::Struct can now define the classes in compile time.
963 Class::Struct now assigns the array/hash element if the accessor
964 is called with an array/hash element as the B<sole> argument.
968 Data::Dumper has now an option to sort hashes.
972 Data::Dumper has now an option to dump code references
977 DB_File now supports newer Berkeley DB versions, among
982 The English module can now be used without the infamous performance
985 use English '-no_match_vars';
987 (Assuming, of course, that one doesn't need the troublesome variables
988 C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
989 C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
993 Fcntl, Socket, and Sys::Syslog have been rewritten to use the
994 new-style constant dispatch section (see L<ExtUtils::Constant>).
995 This means that they will be more robust and hopefully faster.
999 File::Find now chdir()s correctly when chasing symbolic links.
1003 File::Find now has pre- and post-processing callbacks. It also
1004 correctly changes directories when chasing symbolic links. Callbacks
1005 (naughtily) exiting with "next;" instead of "return;" now work.
1009 File::Find is now (again) reentrant. It also has been made
1014 The warnings issued by File::Find now belong to their own category.
1015 You can enable/disable them with C<use/no warnings 'File::Find';>.
1019 File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
1020 prototype mismatch with CORE::glob().
1024 File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
1025 the returned list of filenames.
1029 Devel::Peek now has an interface for the Perl memory statistics
1030 (this works only if you are using perl's malloc, and if you have
1031 compiled with debugging).
1035 IPC::Open3 now allows the use of numeric file descriptors.
1039 IO::Socket has now atmark() method, which returns true if the socket
1040 is positioned at the out-of-band mark. The method is also exportable
1041 as a sockatmark() function.
1045 IO::Socket::INET has support for ReusePort option (if your platform
1046 supports it). The Reuse option now has an alias, ReuseAddr. For clarity
1047 you may want to prefer ReuseAddr.
1051 IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
1052 that the operating system will make one up.)
1056 use lib now works identically to @INC. Removing directories
1057 with 'no lib' now works.
1061 ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
1062 leads into better portability.
1066 Math::BigFloat and Math::BigInt have undergone a full rewrite.
1067 They are now magnitudes faster, and they support various
1068 bignum libraries such as GMP and PARI as their backends.
1072 Math::Complex handles inf, NaN etc., better.
1076 Net::Ping has been muchly enhanced. Multihoming is now supported.
1077 There is now "external" protocol which uses Net::Ping::External module
1078 which runs external ping(1) and parses the output. A version of
1079 Net::Ping::External is available in CPAN.
1083 POSIX::sigaction() is now much more flexible and robust.
1084 You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
1085 handlers, installing new handlers was not atomic.
1089 In Safe the C<%INC> now localised in a Safe compartment so that
1094 In SDBM_File on dosish platforms, some keys went missing because of
1095 lack of support for files with "holes". A workaround for the problem
1100 In Search::Dict one can now have a pre-processing hook for the
1101 lines being searched.
1105 The Shell module now has an OO interface.
1109 The Test module has been significantly enhanced.
1113 The vars pragma now supports declaring fully qualified variables.
1114 (Something that C<our()> does not and will not support.)
1118 The C<utf8::> name space (as in the pragma) provides various
1119 Perl-callable functions to provide low level access to Perl's
1120 internal Unicode representation. At the moment only length()
1121 has been implemented.
1125 =head1 Utility Changes
1131 Emacs perl mode (emacs/cperl-mode.el) has been updated to version
1136 F<emacs/e2ctags.pl> is now much faster.
1140 C<h2ph> now supports C trigraphs.
1144 C<h2xs> now produces a template README.
1148 C<h2xs> now uses C<Devel::PPort> for better portability between
1149 different versions of Perl.
1153 C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
1154 newly created extensions that define constants. Since the new code is
1155 more correct (if you have two constants where the first one is a
1156 prefix of the second one, the first constant B<never> gets defined),
1157 less lossy (it uses integers for integer constant, as opposed to the
1158 old code that used floating point numbers even for integer constants),
1159 and slightly faster, you might want to consider regenerating your
1160 extension code (the new scheme makes regenerating easy).
1161 L<h2xs> now also supports C trigraphs.
1165 C<libnetcfg> has been added to configure the libnet.
1169 C<perlbug> is now much more robust. It also sends the bug report to
1170 perl.org, not perl.com.
1174 C<perlcc> has been rewritten and its user interface (that is,
1175 command line) is much more like that of the UNIX C compiler, cc.
1176 (The perlbc tools has been removed. Use C<perlcc -B> instead.)
1180 C<perlivp> is a new Installation Verification Procedure utility
1181 for running any time after installing Perl.
1185 C<pod2html> now allows specifying a cache directory.
1189 C<s2p> has been completely rewritten in Perl. (It is in fact a full
1190 implementation of sed in Perl: you can use the sed functionality by
1191 using the C<psed> utility.)
1195 C<xsubpp> now understands POD documentation embedded in the *.xs files.
1199 C<xsubpp> now supports OUT keyword.
1203 =head1 New Documentation
1209 perl56delta details the changes between the 5.005 release and the
1214 perlclib documents the internal replacements for standard C library
1215 functions. (Interesting only for extension writers and Perl core
1220 perldebtut is a Perl debugging tutorial.
1224 perlebcdic contains considerations for running Perl on EBCDIC platforms.
1228 perlintro is a gentle introduction to Perl.
1232 perliol documents the internals of PerlIO with layers.
1236 perlmodstyle is a style guide for writing modules.
1240 perlnewmod tells about writing and submitting a new module.
1244 perlpacktut is a pack() tutorial.
1248 perlpod has been rewritten to be clearer and to record the best
1249 practices gathered over the years.
1253 perlpodspec is a more formal specification of the pod format,
1254 mainly of interest for writers of pod applications, not to
1255 people writing in pod.
1259 perlretut is a regular expression tutorial.
1263 perlrequick is a regular expressions quick-start guide.
1264 Yes, much quicker than perlretut.
1268 perltodo has been updated.
1272 perltootc has been renamed as perltooc (to not to conflict
1273 with perltoot in filesystems restricted to "8.3" names)
1277 perluniintro is an introduction to using Unicode in Perl.
1278 (perlunicode is more of a detailed reference and background
1283 perlutil explains the command line utilities packaged with the Perl
1288 The following platform-specific documents are available before
1289 the installation as README.I<platform>, and after the installation
1292 perlaix perlamiga perlapollo perlbeos perlbs2000
1293 perlce perlcygwin perldgux perldos perlepoc perlhpux
1294 perlhurd perlmachten perlmacos perlmint perlmpeix
1295 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1296 perltru64 perluts perlvmesa perlvms perlvos perlwin32
1302 The documentation for the POSIX-BC platform is called "BS2000", to avoid
1303 confusion with the Perl POSIX module.
1307 The documentation for the WinCE platform is called "CE", to avoid
1308 confusion with the perlwin32 documentation on 8.3-restricted filesystems.
1312 =head1 Performance Enhancements
1318 map() could get pathologically slow when the result list it generates
1319 is larger than the source list. The performance has been improved for
1324 sort() has been changed to use primarily mergesort internally as
1325 opposed to the earlier quicksort. For very small lists this may
1326 result in slightly slower sorting times, but in general the speedup
1327 should be at least 20%. Additional bonuses are that the worst case
1328 behaviour of sort() is now better (in computer science terms it now
1329 runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1330 worst-case run time behaviour), and that sort() is now stable
1331 (meaning that elements with identical keys will stay ordered as they
1332 were before the sort). See the C<sort> pragma for information.
1334 The story in more detail: suppose you want to serve yourself a little
1337 @digits = ( 3,1,4,1,5,9 );
1339 A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1340 Which C<1> comes first is hard to know, since one C<1> looks pretty
1341 much like any other. You can regard this as totally trivial,
1342 or somewhat profound. However, if you just want to sort the even
1343 digits ahead of the odd ones, then what will
1345 sort { ($a % 2) <=> ($b % 2) } @digits;
1347 yield? The only even digit, C<4>, will come first. But how about
1348 the odd numbers, which all compare equal? With the quicksort algorithm
1349 used to implement Perl 5.6 and earlier, the order of ties is left up
1350 to the sort. So, as you add more and more digits of Pi, the order
1351 in which the sorted even and odd digits appear will change.
1352 and, for sufficiently large slices of Pi, the quicksort algorithm
1353 in Perl 5.8 won't return the same results even if reinvoked with the
1354 same input. The justification for this rests with quicksort's
1355 worst case behavior. If you run
1357 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1359 (something you might approximate if you wanted to merge two sorted
1360 arrays using sort), doubling $N doesn't just double the quicksort time,
1361 it I<quadruples> it. Quicksort has a worst case run time that can
1362 grow like N**2, so-called I<quadratic> behaviour, and it can happen
1363 on patterns that may well arise in normal use. You won't notice this
1364 for small arrays, but you I<will> notice it with larger arrays,
1365 and you may not live long enough for the sort to complete on arrays
1366 of a million elements. So the 5.8 quicksort scrambles large arrays
1367 before sorting them, as a statistical defence against quadratic behaviour.
1368 But that means if you sort the same large array twice, ties may be
1369 broken in different ways.
1371 Because of the unpredictability of tie-breaking order, and the quadratic
1372 worst-case behaviour, quicksort was I<almost> replaced completely with
1373 a stable mergesort. I<Stable> means that ties are broken to preserve
1374 the original order of appearance in the input array. So
1376 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1378 will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1379 appear in the output in the same order they appeared in the input.
1380 Mergesort has worst case O(NlogN) behaviour, the best value
1381 attainable. And, ironically, this mergesort does particularly
1382 well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1383 in O(N) time. But quicksort was rescued at the last moment because
1384 it is faster than mergesort on certain inputs and platforms.
1385 For example, if you really I<don't> care about the order of even
1386 and odd digits, quicksort will run in O(N) time; it's very good
1387 at sorting many repetitions of a small number of distinct elements.
1388 The quicksort divide and conquer strategy works well on platforms
1389 with relatively small, very fast, caches. Eventually, the problem gets
1390 whittled down to one that fits in the cache, from which point it
1391 benefits from the increased memory speed.
1393 Quicksort was rescued by implementing a sort pragma to control aspects
1394 of the sort. The B<stable> subpragma forces stable behaviour,
1395 regardless of algorithm. The B<_quicksort> and B<_mergesort>
1396 subpragmas are heavy-handed ways to select the underlying implementation.
1397 The leading C<_> is a reminder that these subpragmas may not survive
1398 beyond 5.8. More appropriate mechanisms for selecting the implementation
1399 exist, but they wouldn't have arrived in time to save quicksort.
1403 Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1404 (http://burtleburtle.net/bob/hash/doobs.html). This algorithm is
1405 reasonably fast while producing a much better spread of values than
1406 the old hashing algorithm (originally by Chris Torek, later tweaked by
1407 Ilya Zakharevich). Hash values output from the algorithm on a hash of
1408 all 3-char printable ASCII keys comes much closer to passing the
1409 DIEHARD random number generation tests. According to perlbench, this
1410 change has not affected the overall speed of Perl.
1414 unshift() should now be noticeably faster.
1418 =head1 Installation and Configuration Improvements
1420 =head2 Generic Improvements
1426 INSTALL now explains how you can configure Perl to use 64-bit
1427 integers even on non-64-bit platforms.
1431 Policy.sh policy change: if you are reusing a Policy.sh file
1432 (see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1433 Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1434 them will now be changed to the new prefix, /foo/bar. (Previously
1435 only $prefix changed.) If you do not like this new behaviour,
1436 specify prefix, siteprefix, and vendorprefix explicitly.
1440 A new optional location for Perl libraries, otherlibdirs, is available.
1441 It can be used for example for vendor add-ons without disturbing Perl's
1442 own library directories.
1446 In many platforms the vendor-supplied 'cc' is too stripped-down to
1447 build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1448 to be the case and 'cc' does not seem to be the GNU C compiler
1449 'gcc', an automatic attempt is made to find and use 'gcc' instead.
1453 gcc needs to closely track the operating system release to avoid
1454 build problems. If Configure finds that gcc was built for a different
1455 operating system release than is running, it now gives a clearly visible
1456 warning that there may be trouble ahead.
1460 If binary compatibility with the 5.005 release is not wanted, Configure
1461 no longer suggests including the 5.005 modules in @INC.
1465 Configure C<-S> can now run non-interactively.
1469 Configure support for pdp11-style memory models has been removed due
1474 configure.gnu now works with options with whitespace in them.
1478 installperl now outputs everything to STDERR.
1482 $Config{byteorder} is now computed dynamically (this is more robust
1483 with "fat binaries" where an executable image contains binaries for
1484 more than one binary platform.)
1488 Because PerlIO is now the default on most platforms, "-perlio" doesn't
1489 get appended to the $Config{archname} (also known as $^O) anymore.
1490 Instead, if you explicitly choose not to use perlio (Configure command
1491 line option -Uuseperlio), you will get "-stdio" appended.
1495 Another change related to the architecture name is that "-64all"
1496 (-Duse64bitall, or "maximally 64-bit") is appended only if your
1497 pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1501 In AFS installations one can configure the root of the AFS to be
1502 somewhere else than the default F</afs> by using the Configure
1503 parameter C<-Dafsroot=/some/where/else>.
1507 APPLLIB_EXP, a less-know configuration-time definition, has been
1508 documented. It can be used to prepend site-specific directories
1509 to Perl's default search path (@INC), see INSTALL for information.
1513 The version of Berkeley DB used when the Perl (and, presumably, the
1514 DB_File extension) was built is now available as
1515 C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1516 from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1517 DB_VERSION_PATCH_CFG> from C.
1521 Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1522 has been documented in INSTALL.
1526 If you have CPAN access (either network or a local copy such as a
1527 CD-ROM) you can during specify extra modules to Configure to build and
1528 install with Perl using the -Dextras=... option. See INSTALL for
1533 In addition to config.over a new override file, config.arch, is
1534 available. That is supposed to be used by hints file writers for
1535 architecture-wide changes (as opposed to config.over which is for
1540 If your file system supports symbolic links you can build Perl outside
1541 of the source directory by
1543 mkdir /tmp/perl/build/directory
1544 cd /tmp/perl/build/directory
1545 sh /path/to/perl/source/Configure -Dmksymlinks ...
1547 This will create in /tmp/perl/build/directory a tree of symbolic links
1548 pointing to files in /path/to/perl/source. The original files are left
1549 unaffected. After Configure has finished you can just say
1553 and Perl will be built and tested, all in /tmp/perl/build/directory.
1557 For Perl developers several new make targets for profiling
1558 and debugging have been added, see L<perlhack>.
1564 Use of the F<gprof> tool to profile Perl has been documented in
1565 L<perlhack>. There is a make target called "perl.gprof" for
1566 generating a gprofiled Perl executable.
1570 If you have GCC 3, there is a make target called "perl.gcov" for
1571 creating a gcoved Perl executable for coverage analysis. See
1576 If you are on IRIX or Tru64 platforms, new profiling/debugging options
1577 have been added, see L<perlhack> for more information about pixie and
1584 Guidelines of how to construct minimal Perl installations have
1585 been added to INSTALL.
1589 The Thread extension is now not built at all under ithreads
1590 (C<Configure -Duseithreads>) because it wouldn't work anyway (the
1591 Thread extension requires being Configured with C<-Duse5005threads>).
1593 But note that the Thread.pm interface is now shared by both
1598 The Gconvert macro ($Config{d_Gconvert}) used by perl for stringifying
1599 floating-point numbers is now more picky about using sprintf %.*g
1600 rules for the conversion. Some platforms that used to use gcvt may
1601 now resort to the slower sprintf.
1605 =head2 New Or Improved Platforms
1607 For the list of platforms known to support Perl,
1608 see L<perlport/"Supported Platforms">.
1614 AIX dynamic loading should be now better supported.
1618 AIX should now work better with gcc, threads, and 64-bitness. Also the
1619 long doubles support in AIX should be better now. See L<perlaix>.
1623 After a long pause, AmigaOS has been verified to be happy with Perl.
1627 AtheOS (http://www.atheos.cx/) is a new platform.
1631 BeOS has been reclaimed.
1635 DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
1639 DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
1643 EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1644 have been regained. Many test suite tests still fail and the
1645 co-existence of Unicode and EBCDIC isn't quite settled, but the
1646 situation is much better than with Perl 5.6. See L<perlos390>,
1647 L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
1651 Building perl with -Duseithreads or -Duse5005threads now works under
1652 HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1653 need a thread library package installed. See README.hpux.
1657 MacOS Classic (MacPerl has of course been available since
1658 perl 5.004 but now the source code bases of standard Perl
1659 and MacPerl have been synchronised)
1663 MacOS X (or Darwin) should now be able to build Perl even on HFS+
1664 filesystems. (The case-insensitivity confused the Perl build process.)
1668 NCR MP-RAS is now supported.
1672 All the NetBSD specific patches (except for the installation
1673 specific ones) have been merged back to the main distribution.
1677 NetWare from Novell is now supported. See L<perlnetware>.
1681 NonStop-UX is now supported.
1685 NEC SUPER-UX is now supported.
1689 All the OpenBSD specific patches (except for the installation
1690 specific ones) have been merged back to the main distribution.
1694 Perl has been tested with the GNU pth userlevel thread package
1695 ( http://www.gnu.org/software/pth/pth.html ) . All but one thread
1696 test worked, and that one failure was because of test results arriving
1697 in unexpected order.
1701 Amdahl UTS UNIX mainframe platform is now supported.
1705 WinCE is now supported. See L<perlce>.
1709 z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1710 support for dynamic loading. This is not selected by default,
1711 however, you must specify -Dusedl in the arguments of Configure.
1715 =head1 Selected Bug Fixes
1717 Numerous memory leaks and uninitialized memory accesses have been
1718 hunted down. Most importantly anonymous subs used to leak quite
1725 The autouse pragma didn't work for Multi::Part::Function::Names.
1729 caller() could cause core dumps in certain situations. Carp was sometimes
1730 affected by this problem.
1734 chop(@list) in list context returned the characters chopped in
1735 reverse order. This has been reversed to be in the right order.
1739 Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1740 when building the Perl binary. The only exception to this is SunOS 4.x,
1745 The behaviour of non-decimal but numeric string constants such as
1746 "0x23" was platform-dependent: in some platforms that was seen as 35,
1747 in some as 0, in some as a floating point number (don't ask). This
1748 was caused by Perl using the operating system libraries in a situation
1749 where the result of the string to number conversion is undefined: now
1750 Perl consistently handles such strings as zero in numeric contexts.
1754 The order of DESTROYs has been made more predictable.
1758 Several debugger fixes: exit code now reflects the script exit code,
1759 condition C<"0"> now treated correctly, the C<d> command now checks
1760 line number, the C<$.> no longer gets corrupted, all debugger output
1761 now goes correctly to the socket if RemotePort is set.
1765 Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
1766 when statically building extensions into perl. This has been corrected.
1770 L<dprofpp> -R didn't work.
1774 C<*foo{FORMAT}> now works.
1777 Infinity is now recognized as a number.
1781 UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1782 the Tk extension with 5.6.0.)
1786 Lexicals I: lexicals outside an eval "" weren't resolved
1787 correctly inside a subroutine definition inside the eval "" if they
1788 were not already referenced in the top level of the eval""ed code.
1792 Lexicals II: lexicals leaked at file scope into subroutines that
1793 were declared before the lexicals.
1797 Lexical warnings now propagating correctly between scopes
1798 and into C<eval "...">.
1802 C<use warnings qw(FATAL all)> did not work as intended. This has been
1807 warnings::enabled() now reports the state of $^W correctly if the caller
1808 isn't using lexical warnings.
1812 Line renumbering with eval and C<#line> now works.
1816 Fixed numerous memory leaks, especially in eval "".
1820 mkdir() now ignores trailing slashes in the directory name,
1821 as mandated by POSIX.
1825 Some versions of glibc have a broken modfl(). This affects builds
1826 with C<-Duselongdouble>. This version of Perl detects this brokenness
1827 and has a workaround for it. The glibc release 2.2.2 is known to have
1828 fixed the modfl() bug.
1832 Modulus of unsigned numbers now works (4063328477 % 65535 used to
1833 return 27406, instead of 27047).
1837 Some "not a number" warnings introduced in 5.6.0 eliminated to be
1838 more compatible with 5.005. Infinity is now recognised as a number.
1842 Numeric conversions did not recognize changes in the string value
1843 properly in certain circumstances.
1847 Attributes (like :shared) didn't work with our().
1851 our() variables will not cause "will not stay shared" warnings.
1855 "our" variables of the same name declared in two sibling blocks
1856 resulted in bogus warnings about "redeclaration" of the variables.
1857 The problem has been corrected.
1861 pack "Z" now correctly terminates the string with "\0".
1865 Fix password routines which in some shadow password platforms
1866 (e.g. HP-UX) caused getpwent() to return every other entry.
1870 The PERL5OPT environment variable (for passing command line arguments
1871 to Perl) didn't work for more than a single group of options.
1875 PERL5OPT with embedded spaces didn't work.
1879 printf() no longer resets the numeric locale to "C".
1883 C<qw(a\\b)> now parses correctly as C<'a\\b'>.
1887 pos() did not return the correct value within s///ge in earlier
1888 versions. This is now handled correctly.
1892 Printing quads (64-bit integers) with printf/sprintf now works
1893 without the q L ll prefixes (assuming you are on a quad-capable platform).
1897 Regular expressions on references and overloaded scalars now work.
1901 Right-hand side magic (GMAGIC) could in many cases such as string
1902 concatenation be invoked too many times.
1906 scalar() now forces scalar context even when used in void context.
1910 SOCKS support is now much more robust.
1914 sort() arguments are now compiled in the right wantarray context
1915 (they were accidentally using the context of the sort() itself).
1916 The comparison block is now run in scalar context, and the arguments
1917 to be sorted are always provided list context.
1921 Changed the POSIX character class C<[[:space:]]> to include the (very
1922 rarely used) vertical tab character. Added a new POSIX-ish character
1923 class C<[[:blank:]]> which stands for horizontal whitespace
1924 (currently, the space and the tab).
1928 The tainting behaviour of sprintf() has been rationalized. It does
1929 not taint the result of floating point formats anymore, making the
1930 behaviour consistent with that of string interpolation.
1934 Some cases of inconsistent taint propagation (such as within hash
1935 values) have been fixed.
1939 The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
1940 of simple pattern matches. These are now handled better.
1944 Regular expression debug output (whether through C<use re 'debug'>
1945 or via C<-Dr>) now looks better.
1949 Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
1954 Use of $& could trigger a core dump under some situations. This
1959 The regular expression captured submatches ($1, $2, ...) are now
1960 more consistently unset if the match fails, instead of leaving false
1961 data lying around in them.
1965 readline() on files opened in "slurp" mode could return an extra "" at
1966 the end in certain situations. This has been corrected.
1970 Autovivification of symbolic references of special variables described
1971 in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
1976 Sys::Syslog ignored the C<LOG_AUTH> constant.
1980 All but the first argument of the IO syswrite() method are now optional.
1984 $AUTOLOAD, sort(), lock(), and spawning subprocesses
1985 in multiple threads simultaneously are now thread-safe.
1989 Tie::ARRAY SPLICE method was broken.
1993 Allow read-only string on left hand side of non-modifying tr///.
1997 Several Unicode fixes.
2003 BOMs (byte order marks) in the beginning of Perl files
2004 (scripts, modules) should now be transparently skipped.
2005 UTF-16 (UCS-2) encoded Perl files should now be read correctly.
2009 The character tables have been updated to Unicode 3.1.1.
2013 Comparing with utf8 data does not magically upgrade non-utf8 data
2014 into utf8. (This was a problem for example if you were mixing data
2015 from I/O and Unicode data: your output might have got magically encoded
2020 Generating illegal Unicode code points like U+FFFE, or the UTF-16
2021 surrogates, now also generates an optional warning.
2025 C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
2029 Concatenation with the C<.> operator or via variable interpolation,
2030 C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
2031 substitution with C<s///>, single-quoted UTF8, should now work.
2035 The C<tr///> operator now works. Note that the C<tr///CU>
2036 functionality has been removed (but see pack('U0', ...)).
2040 C<eval "v200"> now works.
2044 Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
2045 This has been corrected.
2049 Zero entries were missing from the Unicode classes like C<IsDigit>.
2055 Large unsigned numbers (those above 2**31) could sometimes lose their
2056 unsignedness, causing bogus results in arithmetic operations.
2060 =head2 Platform Specific Changes and Fixes
2068 Perl now works on post-4.0 BSD/OSes.
2074 Setting C<$0> now works (as much as possible; see L<perlvar> for details).
2080 Numerous updates; currently synchronised with Cygwin 1.3.10.
2084 Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
2090 EPOC update after Perl 5.6.0. See README.epoc.
2096 Perl now works on post-3.0 FreeBSDs.
2102 README.hpux updated; C<Configure -Duse64bitall> now works.
2108 Numerous compilation flag and hint enhancements; accidental mixing
2109 of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
2119 Long doubles should now work (see INSTALL).
2123 Linux previously had problems related to sockaddrlen when using
2124 accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
2132 Compilation of the standard Perl distribution in MacOS Classic should
2133 now work if you have the Metrowerks development environment and
2134 the missing Mac-specific toolkit bits. Contact the macperl mailing
2141 MPE/iX update after Perl 5.6.0. See README.mpeix.
2147 Perl now works on NetBSD/sparc.
2153 Now works with usethreads (see INSTALL).
2159 64-bitness using the Sun Workshop compiler now works.
2163 Tru64 (aka Digital UNIX, aka DEC OSF/1)
2165 The operating system version letter now recorded in $Config{osvers}.
2166 Allow compiling with gcc (previously explicitly forbidden). Compiling
2167 with gcc still not recommended because buggy code results, even with
2174 Fixed various alignment problems that lead into core dumps either
2175 during build or later; no longer dies on math errors at runtime;
2176 now using full quad integers (64 bits), previously was using
2177 only 46 bit integers for speed.
2183 chdir() now works better despite a CRT bug; now works with MULTIPLICITY
2184 (see INSTALL); now works with Perl's malloc.
2186 The tainting of C<%ENV> elements via C<keys> or C<values> was previously
2187 unimplemented. It now works as documented.
2189 The C<waitpid> emulation has been improved. The worst bug (now fixed)
2190 was that a pid of -1 would cause a wildcard search of all processes on
2191 the system. The most significant enhancement is that we can now
2192 usually get the completion status of a terminated process.
2194 POSIX-style signals are now emulated much better on VMS versions prior
2197 The C<system> function and backticks operator have improved
2198 functionality and better error handling.
2200 File access tests now use current process privileges rather than the
2201 user's default privileges, which could sometimes result in a mismatch
2202 between reported access and actual access.
2212 accept() no longer leaks memory.
2216 Borland C++ v5.5 is now a supported compiler that can build Perl.
2217 However, the generated binaries continue to be incompatible with those
2218 generated by the other supported compilers (GCC and Visual C++).
2222 Better chdir() return value for a non-existent directory.
2226 Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
2230 New %ENV entries now propagate to subprocesses.
2234 Current directory entries in %ENV are now correctly propagated to child
2239 $ENV{LIB} now used to search for libs under Visual C.
2243 fork() emulation has been improved in various ways, but still continues
2244 to be experimental. See L<perlfork> for known bugs and caveats.
2248 A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
2252 Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
2253 Other bugs in chdir() and Cwd::cwd() have also been fixed.
2257 HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
2261 The makefiles now provide a single switch to bulk-enable all the features
2262 enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
2266 Allow REG_EXPAND_SZ keys in the registry.
2270 Can now send() from all threads, not just the first one.
2274 Fake signal handling reenabled, bugs and all.
2278 %SIG has been enabled under USE_ITHREADS, but its use is completely
2279 unsupported under all configurations.
2283 Less stack reserved per thread so that more threads can run
2284 concurrently. (Still 16M per thread.)
2288 C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
2289 (works better when perl is running as service).
2293 Better UNC path handling under ithreads.
2297 wait(), waitpid() and backticks now return the correct exit status under
2302 winsock handle leak fixed.
2306 The Perl parser has been stress tested using both random input and
2307 Markov chain input and the few found crashes and lockups have been
2314 =head1 New or Changed Diagnostics
2320 The lexical warnings category "deprecated" is no longer a sub-category
2321 of the "syntax" category. It is now a top-level category in its own
2326 All regular expression compilation error messages are now hopefully
2327 easier to understand both because the error message now comes before
2328 the failed regex and because the point of failure is now clearly
2329 marked by a C<E<lt>-- HERE> marker.
2333 The various "opened only for", "on closed", "never opened" warnings
2334 drop the C<main::> prefix for filehandles in the C<main> package,
2335 for example C<STDIN> instead of C<main::STDIN>.
2339 The "Unrecognized escape" warning has been extended to include C<\8>,
2340 C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
2344 Two new debugging options have been added: if you have compiled your
2345 Perl with debugging, you can use the -DT and -DR options to trace
2346 tokenising and to add reference counts to displaying variables,
2351 perl5db.pl has been modified to present a more consistent commands
2352 interface, via (CommandSet=580). perl5db.t was also added to test the
2353 changes, and as a placeholder for further tests.
2359 The debugger has a new C<dumpDepth> option to control the maximum
2360 depth to which nested structures are dumped. The C<x> command has
2361 been extended so that C<x N EXPR> dumps out the value of I<EXPR> to a
2362 depth of at most I<N> levels.
2366 If an attempt to use a (non-blessed) reference as an array index
2367 is made, a warning is given.
2371 C<push @a;> and C<unshift @a;> (with no values to push or unshift)
2372 now give a warning. This may be a problem for generated and evaled
2377 If you try to L<perlfunc/pack> a number less than 0 or larger than 255
2378 using the C<"C"> format you will get an optional warning. Similarly
2379 for the C<"c"> format and a number less than -128 or more than 127.
2383 Certain regex modifiers such as C<(?o)> make sense only if applied to
2384 the entire regex. You will an optional warning if you try to do otherwise.
2388 Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
2389 has been deprecated for a while. Now you will get an optional warning.
2393 Using C<sort> in scalar context now issues an optional warning.
2394 This didn't do anything useful, as the sort was not performed.
2398 =head1 Changed Internals
2404 perlapi.pod (a companion to perlguts) now attempts to document the
2409 You can now build a really minimal perl called microperl.
2410 Building microperl does not require even running Configure;
2411 C<make -f Makefile.micro> should be enough. Beware: microperl makes
2412 many assumptions, some of which may be too bold; the resulting
2413 executable may crash or otherwise misbehave in wondrous ways.
2414 For careful hackers only.
2418 Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2419 ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2420 interfaces to the publicised API. For the full list of the available
2421 APIs see L<perlapi>.
2425 Made possible to propagate customised exceptions via croak()ing.
2429 Now xsubs can have attributes just like subs. (Well, at least the
2430 built-in attributes.)
2434 dTHR and djSP have been obsoleted; the former removed (because it's
2435 a no-op) and the latter replaced with dSP.
2439 PERL_OBJECT has been completely removed.
2443 The MAGIC constants (e.g. C<'P'>) have been macrofied
2444 (e.g. C<PERL_MAGIC_TIED>) for better source code readability
2445 and maintainability.
2449 The regex compiler now maintains a structure that identifies nodes in
2450 the compiled bytecode with the corresponding syntactic features of the
2451 original regex expression. The information is attached to the new
2452 C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2453 complete information.
2457 The C code has been made much more C<gcc -Wall> clean. Some warning
2458 messages still remain in some platforms, so if you are compiling with
2459 gcc you may see some warnings about dubious practices. The warnings
2460 are being worked on.
2464 F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2468 Documentation on how to use the Perl source repository has been added
2469 to F<Porting/repository.pod>.
2473 There are now several profiling make targets.
2477 =head1 Security Vulnerability Closed
2479 (This change was already made in 5.7.0 but bears repeating here.)
2481 A potential security vulnerability in the optional suidperl component
2482 of Perl was identified in August 2000. suidperl is neither built nor
2483 installed by default. As of November 2001 the only known vulnerable
2484 platform is Linux, most likely all Linux distributions. CERT and
2485 various vendors and distributors have been alerted about the vulnerability.
2486 See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2487 for more information.
2489 The problem was caused by Perl trying to report a suspected security
2490 exploit attempt using an external program, /bin/mail. On Linux
2491 platforms the /bin/mail program had an undocumented feature which
2492 when combined with suidperl gave access to a root shell, resulting in
2493 a serious compromise instead of reporting the exploit attempt. If you
2494 don't have /bin/mail, or if you have 'safe setuid scripts', or if
2495 suidperl is not installed, you are safe.
2497 The exploit attempt reporting feature has been completely removed from
2498 Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2499 from all the Perl 5.7 releases), so that particular vulnerability
2500 isn't there anymore. However, further security vulnerabilities are,
2501 unfortunately, always possible. The suidperl functionality is most
2502 probably going to be removed in Perl 5.10. In any case, suidperl
2503 should only be used by security experts who know exactly what they are
2504 doing and why they are using suidperl instead of some other solution
2505 such as sudo (see http://www.courtesan.com/sudo/).
2509 Several new tests have been added, especially for the F<lib>
2510 subsection. There are now about 56 000 individual tests (spread over
2511 about 620 test scripts), in the regression suite (5.6.1 has about
2512 11700 tests, in 258 test scripts) Many of the new tests are introduced
2513 by the new modules, but still in general Perl is now more thoroughly
2516 Because of the large number of tests, running the regression suite
2517 will take considerably longer time than it used to: expect the suite
2518 to take up to 4-5 times longer to run than in perl 5.6. In a really
2519 fast machine you can hope to finish the suite in about 6-8 minutes
2522 The tests are now reported in a different order than in earlier Perls.
2523 (This happens because the test scripts from under t/lib have been moved
2524 to be closer to the library/extension they are testing.)
2526 =head1 Known Problems
2534 In AIX 4.2 Perl extensions that use C++ functions that use statics
2535 may have problems in that the statics are not getting initialized.
2536 In newer AIX releases this has been solved by linking Perl with
2537 the libC_r library, but unfortunately in AIX 4.2 the said library
2538 has an obscure bug where the various functions related to time
2539 (such as time() and gettimeofday()) return broken values, and
2540 therefore in AIX 4.2 Perl is not linked against the libC_r.
2544 vac 5.0.0.0 May Produce Buggy Code For Perl
2546 The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2547 resulting in few random tests failing, but when the failing tests
2548 are run by hand, they succeed. We suggest upgrading to at least
2549 vac version 5.0.1.0, that has been known to compile Perl correctly.
2550 "lslpp -L|grep vac.C" will tell you the vac version. See README.aix.
2554 =head2 Amiga Perl Invoking Mystery
2556 One cannot call Perl using the C<volume:> syntax, that is, C<perl -v>
2557 works, but for example C<bin:perl -v> doesn't. The exact reason isn't
2558 known but the current suspect is the F<ixemul> library.
2560 =head2 lib/ftmp-security tests warn 'system possibly insecure'
2562 Don't panic. Read INSTALL 'make test' section instead.
2564 =head2 FreeBSD 4.3, 4.4, 4.5 fail lib/File/Spec/t/rel2abs2rel.t
2566 F<lib/File/Spec/t/rel2abs2rel.t> tests that "`` works" by running a a perl 1
2567 liner in backticks, using "$^X" as the path to perl. It is known to be
2568 failing on FreeBSD 4.3, 4.4 and 4.5, but only when run as part of make test.
2569 This seems to be a kernel problem rather than perl - reading the symlink
2570 F</proc/curproc/file> returns "unknown" rather than the path to perl, and a
2571 kernel debugger reveals that variable C<numfullpathfail2> in
2572 F</usr/src/sys/kern/vfs_cache.c> is being incremented whenever
2573 F</proc/curproc/file> fails to return the perl executable's path.
2574 [If you find that if fails on other versions of FreeBSD, please use perlbug
2575 to report them to us. If you are able to fix the bug, even better.]
2577 =head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2579 If perl is configured with -Duse64bitall, the successful result of the
2580 subtest 10 of lib/posix may arrive before the successful result of the
2581 subtest 9, which confuses the test harness so much that it thinks the
2584 =head2 Linux With Sfio Fails op/misc Test 48
2590 The following tests are known to fail:
2592 Failed Test Stat Wstat Total Fail Failed List of Failed
2593 -------------------------------------------------------------------------
2594 ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
2595 ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
2596 ../ext/POSIX/t/posix.t 31 1 3.23% 10
2598 If you are building on a UFS partition, you will also probably see
2599 t/op/stat.t subtest #9 fail. This is caused by Darwin's UFS not
2600 supporting inode change time.
2604 OS/390 has rather many test failures but the situation is actually
2605 better than it was in 5.6.0, it's just that so many new modules and
2606 tests have been added.
2608 ../ext/B/t/deparse.t 17 1 5.88% 14
2609 ../ext/IO/lib/IO/t/io_unix.t 5 4 80.00% 2-5
2610 ../lib/utf8.t 94 13 13.83% 27 30-31 43 46 73
2613 ../lib/Benchmark.t 1 256 159 1 0.63% 75
2614 ../lib/ExtUtils/t/Embed.t 9 9 100.00% 1-9
2615 ../lib/ExtUtils/t/ExtUtils.t 27 19 70.37% 5-23
2616 op/pat.t 858 9 1.05% 242-243 665 776 785
2618 op/sprintf.t 224 3 1.34% 98 100 136
2619 op/tr.t 97 5 5.15% 63 71-74
2620 uni/fold.t 767 8 1.04% 25-26 62 169 196
2622 57 tests and 377 subtests skipped.
2624 =head2 op/sprintf tests 129 and 130
2626 The op/sprintf tests 129 and 130 are known to fail on some platforms.
2627 Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2628 The failing platforms do not comply with the ANSI C Standard, line
2629 19ff on page 134 of ANSI X3.159 1989 to be exact. (They produce
2630 something other than "1" and "-1" when formatting 0.6 and -0.6 using
2631 the printf format "%.0f", most often they produce "0" and "-0".)
2633 =head2 Failure of Thread tests
2635 B<Note that support for 5.005-style threading remains experimental
2636 and practically unsupported.>
2638 The following tests are known to fail due to fundamental problems in
2639 the 5.005 threading implementation. These are not new failures--Perl
2640 5.005_0x has the same bugs, but didn't have these tests.
2642 ../ext/List/Util/t/first.t 255 65280 7 4 57.14% 2 5-7
2643 ../lib/English.t 2 512 54 2 3.70% 2-3
2644 ../lib/Filter/Simple/t/data.t 6 3 50.00% 1-3
2645 ../lib/Filter/Simple/t/filter_onl 9 3 33.33% 1-2 5
2646 ../lib/autouse.t 10 1 10.00% 4
2647 op/flip.t 15 1 6.67% 15
2649 These failures are unlikely to get fixed as the 5.005-style
2650 threads are considered fundamentally broken.
2654 ../ext/Socket/socketpair.t 1 256 45 1 2.22% 12
2655 ../lib/Math/Trig.t 26 1 3.85% 25
2656 ../lib/warnings.t 460 1 0.22% 425
2657 io/fs.t 36 1 2.78% 31
2658 op/numconvert.t 1440 13 0.90% 208 509-510
2659 657-658 665-666 829-830 989-990 1149-1150
2661 =head2 UNICOS and UNICOS/mk
2663 The io/fs test #31 is failing because in UNICOS and UNICOS/mk
2664 truncate() cannot be used to grow the size of filehandles, only
2665 to reduce the size. The workaround is to truncate files instead
2670 There are a few known test failures, see L<perluts>.
2674 There should be no reported test failures with a default configuration,
2675 though there are a number of tests marked TODO that point to areas
2676 needing further debugging and/or porting work.
2680 In multi-CPU boxes there are some problems with the I/O buffering:
2681 some output may appear twice. The Win32 following failures are known
2684 ..\ext/Encode/t/JP.t 4 1024 22 4 18.18% 9 14 18 21
2685 ..\ext/threads/t/end.t 6 4 66.67% 3-6
2686 ..\lib/blib.t 3 768 7 3 42.86% 1 4-5
2688 =head2 Localising a Tied Variable Leaks Memory
2691 tie my %tie_hash => 'Tie::StdHash';
2695 local($tie_hash{Foo}) = 1; # leaks
2697 Code like the above is known to leak memory every time the local()
2700 =head2 Localising Tied Arrays and Hashes Is Broken
2704 doesn't work as one would expect: the old value is restored
2707 =head2 Self-tying of Arrays and Hashes Is Forbidden
2709 Self-tying of arrays and hashes is broken in rather deep and
2710 hard-to-fix ways. As a stop-gap measure to avoid people from getting
2711 frustrated at the mysterious results (core dumps, most often) it is
2712 for now forbidden (you will get a fatal error even from an attempt).
2714 =head2 Building Extensions Can Fail Because Of Largefiles
2716 Some extensions like mod_perl are known to have issues with
2717 `largefiles', a change brought by Perl 5.6.0 in which file offsets
2718 default to 64 bits wide, where supported. Modules may fail to compile
2719 at all or compile and work incorrectly. Currently there is no good
2720 solution for the problem, but Configure now provides appropriate
2721 non-largefile ccflags, ldflags, libswanted, and libs in the %Config
2722 hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
2723 having problems can try configuring themselves without the
2724 largefileness. This is admittedly not a clean solution, and the
2725 solution may not even work at all. One potential failure is whether
2726 one can (or, if one can, whether it's a good idea) link together at
2727 all binaries with different ideas about file offsets, all this is
2730 =head2 Unicode Support on EBCDIC Still Spotty
2732 Though mostly working, Unicode support still has problem spots on
2733 EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
2734 regular expression constructs for code points less than 256: the
2735 pP are testing for Unicode code points, not knowing about EBCDIC.
2737 =head2 The Compiler Suite Is Still Experimental
2739 The compiler suite is slowly getting better but it continues to be
2740 highly experimental. Use in production environments is discouraged.
2742 =head2 The Long Double Support Is Still Experimental
2744 The ability to configure Perl's numbers to use "long doubles",
2745 floating point numbers of hopefully better accuracy, is still
2746 experimental. The implementations of long doubles are not yet
2747 widespread and the existing implementations are not quite mature
2748 or standardised, therefore trying to support them is a rare
2749 and moving target. The gain of more precision may also be offset
2750 by slowdown in computations (more bits to move around, and the
2751 operations are more likely to be executed by less optimised
2754 =head2 Seen In Perl 5.7 But Gone Now
2756 C<Time::Piece> (previously known as C<Time::Object>) was removed
2757 because it was felt that it didn't have enough value in it to be a
2758 core module. It is still a useful module, though, and is available
2761 =head1 Reporting Bugs
2763 If you find what you think is a bug, you might check the articles
2764 recently posted to the comp.lang.perl.misc newsgroup and the perl
2765 bug database at http://bugs.perl.org. There may also be
2766 information at http://www.perl.com/, the Perl Home Page.
2768 If you believe you have an unreported bug, please run the B<perlbug>
2769 program included with your release. Be sure to trim your bug down
2770 to a tiny but sufficient test case. Your bug report, along with the
2771 output of C<perl -V>, will be sent off to perlbug@perl.org to be
2772 analysed by the Perl porting team.
2776 The F<Changes> file for exhaustive details on what changed.
2778 The F<INSTALL> file for how to build Perl.
2780 The F<README> file for general stuff.
2782 The F<Artistic> and F<Copying> files for copyright information.
2786 Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.